amp input for door speakers

I know this is gonna sound stupid.. but I've never amped my door speakers before but i'm about to replace all my door speakers with new 6.5's.  I have a 96 blazer so I will have 4 speakers.  My deck has 2 rca outputs, one of which i use for my subs.  When I hook an amp up for my doors, what is the best signal to input to it?  Do i use the other RCA jack?  And if so... will my balance and fader still work on my deck?Donnie

If your deck has one set of full-range RCA jacks and one set of SUB-level RCA jacks, then you will indeed lose front-rear fade by using the one set of RCAs to drive all four channels.  This would be, unfortunately, your only option without adding equipment.  If your sub is currently running off a set of RCAs that are designed as a rear full-range output, simple use a y-connector to drive both your rear channels and the sub amp.Support the12volt.com

so if thats the case and I split the rears.. and hook my fronts to the other input..i wont use the speaker wires coming out of the back of the deck at all .. right?Donnie

and... if only one set is full range... i dont wanna lose my front/rear fader so isnt there a converter to change my original speaker output signals to rca signals?Donnie

If you have four-channels of RCA output, then yes, split one of them for the sub and you will not use the speaker wires at all, tape them off.  If you only have one full-range output, use it for the front channels (and tape off the speaker wires from your deck for the front) and obtain a line-output level converter to change your rear speaker output into an RCA line-level signal, and use this to drive the rear channels on your full-range amp, keeping your sub connected as it is.Support the12volt.com

thanx.Donnie